U.S. patent application number 11/236479 was filed with the patent office on 2006-09-28 for using a fixed network wireless data collection system to improve utility responsiveness to power outages.
This patent application is currently assigned to Elster Electricity LLC. Invention is credited to Andrew J. Borleske, Robert T. Mason, Kenneth J. Shuey.
Application Number | 20060217936 11/236479 |
Document ID | / |
Family ID | 37024455 |
Filed Date | 2006-09-28 |
United States Patent
Application |
20060217936 |
Kind Code |
A1 |
Mason; Robert T. ; et
al. |
September 28, 2006 |
Using a fixed network wireless data collection system to improve
utility responsiveness to power outages
Abstract
A system for determining a service outages and restorations that
includes an outage management server (OMS) that generates reports
outages and restoration information for metering endpoints. The
outages may be caused by faults at various locations in the
distribution network. The metering endpoint may include a
transmitter having a battery backup that transmits the outage
information upon a failure to detect a voltage at the endpoint. The
transmission of the information may be filtered based on
configurable criteria. The metering endpoints may also inform the
OMS when power is restored. Thus, a utility may better service its
customers by focusing manpower efforts using the outage and
restoration information generated by the OMS.
Inventors: |
Mason; Robert T.; (Raleigh,
NC) ; Borleske; Andrew J.; (Garner, NC) ;
Shuey; Kenneth J.; (Zebulon, NC) |
Correspondence
Address: |
WOODCOCK WASHBURN LLP
ONE LIBERTY PLACE, 46TH FLOOR
1650 MARKET STREET
PHILADELPHIA
PA
19103
US
|
Assignee: |
Elster Electricity LLC
Raleigh
NC
27610
|
Family ID: |
37024455 |
Appl. No.: |
11/236479 |
Filed: |
September 27, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60664042 |
Mar 22, 2005 |
|
|
|
Current U.S.
Class: |
702/188 |
Current CPC
Class: |
H04Q 9/00 20130101; H04L
67/125 20130101; H04W 84/18 20130101; Y04S 20/36 20130101; Y04S
20/42 20130101; Y02B 90/246 20130101; Y04S 20/322 20130101; H04W
24/04 20130101; H04Q 2209/60 20130101; Y04S 20/30 20130101; G01D
4/004 20130101; H04M 11/002 20130101; Y02B 90/242 20130101; Y02B
90/20 20130101 |
Class at
Publication: |
702/188 |
International
Class: |
G06F 11/00 20060101
G06F011/00 |
Claims
1. A system for determining outage and restoration information for
meters operating within a fixed wireless metering network,
comprising: a network configuration server that determines a
network state; and an outage management system that determines
outage conditions and power restoration conditions to determine
meters affected by said outage conditions and power restoration
conditions.
2. The system of claim 1, further comprising: a collector; and
metering points, wherein said metering points collect and forward
said outage information to said collector.
3. The system of claim 2, wherein said collector and said metering
points perform filtering of said outage information.
4. The system of claim 3, wherein filtering comprises at least one
of: configurable delays at said metering points prior to
transmitting an outage message, configurable delays at said
metering points prior to transmitting a restoration message,
configurable options in said collector that allow data to be
aggregated prior to a communicating with said outage management
system, and configurable options in said collector that allow
communications to be suppressed during a large-scale outage.
5. The system of claim 2, wherein said metering points select a
random transmit slot within a predetermined transmission
periods.
6. The system of claim 2, wherein said metering points and said
collector are adapted to verify a presence of power by measuring a
voltage.
7. The system of claim 2, wherein a subset of affected metering
points are identified, and wherein said subset of affected metering
points are assigned to a corresponding subset of collectors for
verification of power outage or power restoration.
8. The system of claim 2, wherein said collector is adapted to ping
said metering points to determine an extent of the outage, wherein
said ping comprises one of: a ping each metering point directly, a
ping of metering points in a communication path to determine if
said communication path is available, and a ping of metering points
farthest from said collector first in an attempt to validate all
metering points in the communication path with one message.
9. The system of claim 2, wherein said collector communicates power
restoration information to said outage management system and
wherein said collector receives power restoration information for
said metering points.
10. The system of claim 1, wherein said fixed wireless network
comprises a mesh network that enables said meters to change
communication paths.
11. The system of claim 1, further comprising: a collector; and
metering points, wherein said collector periodically communicates
with said metering points to establish a communication performance
rate.
12. The system of claim 11, wherein said collector sets a
"potential outage" indication after a successive number of
communication failures to a given metering point.
13. The system of claim 12, wherein the number of successive
failures required to set a "potential outage" flag is determined
based on the established communication performance rate between the
collector and the meter.
14. A method for determining outage and restoration information for
meters operating within a fixed wireless metering network,
comprising: maintaining a network state; receiving outage and
restoration communications from communication nodes in said fixed
wireless network; and determining locations affected by said outage
conditions and power restoration conditions.
15. The method of claim 11, further comprising forwarding outage
and restoration communications from metering points associated with
said locations to said communication nodes.
16. The method of claim 12, further comprising filtering said
outage information to configure: delays in transmitting an outage
message, delays prior to transmitting a restoration message,
options that allow data to be aggregated prior to a communicating
with an outage management system, and options that allow
communications to be suppressed during a large-scale outage.
17. The method of claim 12, further comprising: identifying a
subset of affected metering points; and assigning a subset of
communications nodes to verify power outage conditions or power
restoration conditions.
18. The method of claim 12, further comprising pinging said
metering points to determine an extent of the outage.
19. The method of claim 11, further comprising superimposing a
Geographic Information System (GIS) overlay over a distribution
network topology to provide additional information regarding said
outage conditions.
20. A method of determining power outage conditions and power
restoration conditions in an electrical distribution network having
metering endpoints that communicate via a fixed wireless network,
comprising: determining the existence of said power outage
conditions or said power restoration conditions at said metering
endpoints; forwarding information regarding said power outage
conditions or said power restoration conditions to a network
management server via said fixed wireless network; and notifying an
outage management system regarding said power outage conditions or
said power restoration conditions.
21. The method of claim 17, further comprising filtering said
information regarding said power outage conditions or said power
restoration conditions at a collector provided in said fixed
wireless network, said filtering providing for at least delays in
communicating and aggregation of said information.
22. The method of claim 17, further comprising pinging said
metering points to determine the extent of said outage
conditions.
23. The method of claim 17, further comprising superimposing a
Geographic Information System (GIS) overlay over said distribution
network topology to provide additional information regarding said
outage conditions.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority of U.S.
Provisional Patent Application No. 60/664,042, filed Mar. 22,
2005.
FIELD OF THE INVENTION
[0002] The present invention relates to wireless networks for
collecting data, and more particularly, to systems and methods for
monitoring utility system outages using a fixed network wireless
data collection system to improve a utility's response thereto.
BACKGROUND OF THE INVENTION
[0003] The collection of meter data from electrical energy, water,
and gas meters has traditionally been performed by human
meter-readers. The meter-reader travels to the meter location,
which is frequently on the customer's premises, visually inspects
the meter, and records the reading. The meter-reader may be
prevented from gaining access to the meter as a result of inclement
weather or, where the meter is located within the customer's
premises, due to an absentee customer. This methodology of meter
data collection is labor intensive, prone to human error, and often
results in stale and inflexible metering data.
[0004] Some meters have been enhanced to include a one-way radio
transmitter for transmitting metering data to a receiving device. A
person collecting meter data that is equipped with an appropriate
radio receiver need only come into proximity with a meter to read
the meter data and need not visually inspect the meter. Thus, a
meter-reader may walk or drive by a meter location to take a meter
reading. While this represents an improvement over visiting and
visually inspecting each meter, it still requires human involvement
in the process.
[0005] An automated means for collecting meter data involves a
fixed wireless network. Devices such as, for example, repeaters and
gateways are permanently affixed on rooftops and pole-tops and
strategically positioned to receive data from enhanced meters
fitted with radio-transmitters. Typically, these transmitters
operate in the 902-928 MHz range and employ Frequency Hopping
Spread Spectrum (FHSS) technology to spread the transmitted energy
over a large portion of the available bandwidth.
[0006] Data is transmitted from the meters to the repeaters and
gateways and ultimately communicated to a central location. While
fixed wireless networks greatly reduce human involvement in the
process of meter reading, such systems require the installation and
maintenance of a fixed network of repeaters, gateways, and servers.
Identifying an acceptable location for a repeater or server and
physically placing the device in the desired location on top of a
building or utility pole is a tedious and labor-intensive
operation. Furthermore, each meter that is installed in the network
needs to be manually configured to communicate with a particular
portion of the established network. When a portion of the network
fails to operate as intended, human intervention is typically
required to test the effected components and reconfigure the
network to return it to operation.
[0007] Thus, while existing fixed wireless systems have reduced the
need for human involvement in the daily collection of meter data,
such systems may provide benefits to utilities by monitoring for
system outages. In so doing, fixed wireless systems may improve the
utilities response to outages, improving customer service.
SUMMARY OF THE INVENTION
[0008] The present invention is directed to methods and systems for
determining service outages and restorations that includes an
outage management server (OMS) that generates reports of outages
and restoration information for metering endpoints. The outages may
be caused by faults at various locations in the distribution
network. The metering endpoint may include a transmitter having a
battery backup that transmits the outage information upon a failure
to detect a voltage at the endpoint. The transmission of the
information may be filtered based on configurable criteria. The
metering endpoints may also inform the OMS when power is restored.
Thus, a utility may better service its customers by focusing
manpower efforts using the outage and restoration information
generated by the OMS.
[0009] In accordance with the present invention, there is provided
a system for determining outage and restoration information for
meters operating within a fixed wireless metering network. The
system includes a network configuration server that determines a
network states; and an outage management system (OMS) that
determines outage conditions and power restoration conditions. The
OMS may provide a list of meters affected by the power outage and
restoration conditions.
[0010] The system may also include a collector and non-collector
metering points. The non-collector metering points may collect and
forward the outage information to the collector. The collector and
the non-collector metering points may perform filtering of the
outage information. The filtering may comprise at least one of:
configurable delays at the non-collector metering points prior to
transmitting an outage message, configurable delays at the
non-collector metering points prior to transmitting a restoration
message, configurable options in the collector that allow data to
be aggregated prior to a call-in to the outage management system,
and configurable options in the collector that allow call-ins to be
suppressed during a large-scale outage.
[0011] The non-collector metering points may also select a random
transmit slot within a first transmit period, a second transmit
period, and a third transmit period.
[0012] The non-collector metering points and the collector may be
adapted to verify a presence of power by measuring a voltage.
[0013] A subset of affected metering points may be identified, and
the subset of affected metering points assigned to a corresponding
subset of collectors for verification of power outage or power
restoration.
[0014] The collector may be adapted to ping the non-collector
metering points to determine an extent of the outage, wherein the
ping comprises one of: a ping of each non-collector metering point
directly, a ping of non-collector metering points in a
communication path to determine if the communication path is
available, and a ping of non-collector metering points farthest
from the collector first in an attempt to validate all
non-collector metering points in the communication path with one
message.
[0015] Additional features and advantages of the invention will be
made apparent from the following detailed description of
illustrative embodiments that proceeds with reference to the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The foregoing summary, as well as the following detailed
description of preferred embodiments, is better understood when
read in conjunction with the appended drawings. For the purpose of
illustrating the invention, there is shown in the drawings
exemplary constructions of the invention; however, the invention is
not limited to the specific methods and instrumentalities
disclosed. In the drawings:
[0017] FIG. 1 is a diagram of a wireless system for collecting data
from remote devices;
[0018] FIG. 2 expands upon the diagram of FIG. 1 and illustrates a
system in which the present invention is embodied; and
[0019] FIG. 3 illustrates a typical distribution circuit and
potential fault locations.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0020] Exemplary systems and methods for gathering meter data are
described below with reference to FIGS. 1-3. It will be appreciated
by those of ordinary skill in the art that the description given
herein with respect to those figures is for exemplary purposes only
and is not intended in any way to limit the scope of potential
embodiments.
[0021] Generally, a plurality of meter devices, which operate to
track usage of a service or commodity such as, for example,
electricity, water, and gas, are operable to wirelessly communicate
with each other. A collector is operable to automatically identify
and register meters for communication with the collector. When a
meter is installed, the meter registers with a collector that can
provide a communication path to the meter. The collectors receive
and compile metering data from a plurality of meter devices via
wireless communications. A communications server communicates with
the collectors to retrieve the compiled meter data.
[0022] FIG. 1 provides a diagram of an exemplary metering system
110. System 110 comprises a plurality of meters 114, which are
operable to sense and record usage of a service or commodity such
as, for example, electricity, water, or gas. Meters 114 may be
located at customer premises such as, for example, a home or place
of business. Meters 114 comprise an antenna and are operable to
transmit data, including service usage data, wirelessly. Meters 114
may be further operable to receive data wirelessly as well. In an
illustrative embodiment, meters 114 may be, for example, electrical
meters manufactured by Elster Electricity, LLC.
[0023] System 110 further comprises collectors 116. Collectors 116
are also meters operable to detect and record usage of a service or
commodity such as, for example, electricity, water, or gas.
Collectors 116 comprise an antenna and are operable to send and
receive data wirelessly. In particular, collectors 116 are operable
to send data to and receive data from meters 114. In an
illustrative embodiment, collectors 116 may be, for example, an
electrical meter manufactured by Elster Electricity, LLC.
[0024] A collector 116 and the meters 114 for which it is
configured to receive meter data define a subnet/LAN 120 of system
110. As used herein, meters 114 and collectors 116 maybe considered
as nodes in the subnet 120. For each subnet/LAN 120, data is
collected at collector 116 and periodically transmitted to a data
collection server 206. The data collection server 206 stores the
data for analysis and preparation of bills. The data collection
server 206 may be a specially programmed general purpose computing
system and may communicate with collectors 116 wirelessly or via a
wire line connection such as, for example, a dial-up telephone
connection or fixed wire network.
[0025] Generally, collector 116 and meters 114 communicate with and
amongst one another using any one of several robust wireless
techniques such as, for example, frequency hopping spread spectrum
(FHSS) and direct sequence spread spectrum (DSSS). As illustrated,
meters 114a are "first level" meters that communicate with
collector 116, whereas meters 114b are higher level meters that
communicate with other meters in the network that forward
information to the collector 116.
[0026] Referring now to FIG. 2, there is illustrated a system 200
in which the present invention may be embodied. The system 200
includes a network management server (NMS)/metering automation
server (MAS) 202 (the two terms are used interchangeably herein), a
network management system (NMS) 204 and a data collection server
206 that together manage one or more subnets/LANs 120 and their
constituent nodes. The NMS 204 tracks changes in network state,
such as new nodes registering/unregistering with the system 200,
node communication paths changing, etc. This information is
collected for each subnet/LAN 120 and are detected and forwarded to
the network management server 202 and data collection server
206.
[0027] In accordance with an aspect of the invention, communication
between nodes and the system 200 is accomplished using the LAN ID,
however it is preferable for customers to query and communicate
with nodes using their own identifier. To this end, a marriage file
208 may be used to correlate a customer serial number, a
manufacturer serial number and LAN ID for each node (e.g., meters
114a and collectors 116) in the subnet/LAN 120. A device
configuration database 210 stores configuration information
regarding the nodes. For example, in the metering system 110, the
device configuration database may include data regarding time of
use (TOU) switchpoints, etc. for the meters 114a and collectors 116
communicating to the system 200. A data collection requirements
database 212 contains information regarding the data to be
collected on a per node basis. For example, a user may specify that
metering data such as load profile, demand, TOU, etc. is to be
collected from particular meter(s) 114a. Reports 214 containing
information on the network configuration may be automatically
generated or in accordance with a user request.
[0028] The network management system (NMS) 204 maintains a database
describing the current state of the global fixed network system
(current network state 220) and a database describing the
historical state of the system (historical network state 222). The
current network state 220 contains data regarding current meter to
collector assignments, etc. for each subnet/LAN 120. The historical
network state 222 is a database from which the state of the network
at a particular point in the past can be reconstructed. The NMS 204
is responsible for, amongst other things, providing reports 214
about the state of the network. The NMS 204 may be accessed via an
API 220 that is exposed to a user interface 216 and a Customer
Information System (CIS) 218. Other external interfaces may be
implemented in accordance with the present invention. In addition,
the data collection requirements stored in the database 212 may be
set via the user interface 216 or CIS 218.
[0029] The data collection server 206 collects data from the nodes
(e.g., collectors 116) and stores the data in a database 224. The
data includes metering information, such as energy consumption and
may be used for billing purposes, etc. by a utility provider.
[0030] The network management server 202, network management system
204 and data collection server 206 communicate with the nodes in
each subnet/LAN 120 via a communication system 226. The
communication system 226 may be a Frequency Hopping Spread Spectrum
radio network, a mesh network, a Wi-Fi (802.11) network, a Wi-Max
(802.16) network, a land line (POTS) network, etc., or any
combination of the above and enables the system 200 to communicate
with the metering system 110.
[0031] The mesh network automatically builds and re-configures
itself, based on the most reliable communications paths, with each
meter being able to function as a repeater if needed. While the
mesh radio network provides robust communications to the end-point
meters, and allows for communication paths to change if
communications are obstructed, the communication network generally
does not correspond to the physical distribution circuit.
[0032] The overall system of FIG. 2 includes such features as
two-way communications to and from each electricity meter 114a/b.
This enables on-request verification of communications to an
individual meter or to a group of meters, on-request retrieval of
meter data, remote meter re-configuration, critical tier pricing,
and remote actions such as service disconnect. The system operates
over an intelligent meter communications mesh network for path
diversity and self healing. The Metering Automation Server (MAS)
unifies the mesh communication network, schedules meter data
collection and billing dates, and provides meter network management
information. Billing data may be calculated by and stored in the
meter 114a/b. The meter has data processing for functions such as
Time-of-Use (TOU) metering, demand calculations, sum or net
metering, and load profile data. The system architecture allows for
new utility applications such as demand response or demand side
management programs, energy management or home automation systems,
and distribution automation.
[0033] The system 200 consists of three levels: the Metering
Automation Server (MAS)/Network Management Server 202 for operation
and data collection, the collectors 116, and electric meters with
integrated two-way 900 MHz radios for residential and commercial
metering. The system 200 may comprise the EnergyAxis system
available from Elster Electricity LLC, Raleigh, N.C. The collectors
116 may comprise an A3 ALPHA Meter and the meters 114a/114b may
comprise A3 ALPHA or REX meters, which are available from Elster
Electricity LLC, Raleigh, N.C.
[0034] The system 200 may be used to determine an outage and aiding
a utility's response thereto. Utilities continue to look for ways
to improve customer service while reducing operating costs. The use
of a wireless data collection system 200 can help achieve both
goals. One area the utilities may seek to improve is customer
service when an outage occurs. A second area is the efficient
utilization of manpower to restore power. The present invention
implants features in the system 200 to improve customer service and
the efficiency of manpower utilization during outages.
[0035] The word "outage" may have different meanings depending on
who is analyzing the event. IEEE 1159 defines an interruption in
categories depending on the voltage variation (in per unit) and
duration as shown in Table 1 below. TABLE-US-00001 TABLE 1 Typical
Typical Category Duration Voltage Variation Interruption, Sustained
>1 min 0.0 pu Interruption, Temporary 3 s-1 m.sup. <0.1 pu
Interruption, Momentary 0.5 s-3 s <0.1 pu
[0036] Utilities may also have their own definition for an outage.
While momentary and temporary outages are useful in power quality
analysis, they are not of interest to utility personnel responsible
for power restoration. A sustained interruption occurs when a fault
has been cleared by a fuse, recloser, or circuit breaker and it
results in an outage for customers downstream of the protective
device. It is the sustained outage that has the greatest impact on
customers.
[0037] Sources of an Outage
[0038] A customer outage can be caused by several different events.
While an outage is typically caused by the clearing of a fault on
the distribution system, it may also be caused by a fault or open
circuit on the customer premises. FIG. 3 shows a typical
distribution circuit with various fault locations that could result
in a customer outage. For each of the faults shown, the clearing
mechanism and customer impact are summarized.
[0039] Fault at F1: For a fault at F1, the fault is on the customer
premises 300 and is cleared by an in-home circuit breaker resulting
in a loss of power for the customer. Only one customer is
affected.
[0040] Fault at F2: For a fault at F2, the fault is on distribution
line 302 between a fused transformer and the customer premises 300
and would be cleared by the transformer fuse. Typically one to
three customers are affected.
[0041] Fault at F3: For a fault at F3, the fault is on the
distribution lateral 304 and is cleared by a fuse on the
distribution lateral 304. Typically, at least one hundred customers
are affected.
[0042] Fault at F4: For a fault at F4, the fault is on the
distribution line 306 and would be cleared by a line recloser or
station breaker with reclosing relay. Typically, at least three
hundred customers are affected.
[0043] Fault at F5: For a fault at F5, the fault is on the
transmission line 308 and would be cleared by a station breaker.
Typically, at least one thousand customers are affected.
[0044] Utility Response to an Outage
[0045] Following an outage on the distribution grid, utilities want
to be able to restore power to customers in as timely a manner as
possible. One of the major factors that may influence what type of
data a utility wants during an outage is the number of affected
customers.
[0046] As shown FIG. 3, the location of the fault impacts the
numbers of customer affected. When the number of affected customers
is small, the likelihood of the outage being reported is small.
This is particularly true of homes that are not occupied at the
time of the outage (e.g. vacation homes or locations where no one
is home at the time of the outage). Notification is therefore
important so that the outage may be recognized and repair crews
dispatched. For faults involving a large number of customers, the
utility is more likely to receive calls from some of those
customers. A large-scale outage often results in an overload of the
trouble call system due to the large number of customers reporting
the outage. In this case, the initial notification is less
important, but it is important to verify that power has been
restored to all customers.
[0047] The data for utilities as a function of fault location is
summarized in Table 2. TABLE-US-00002 TABLE 2 Utility Drivers
Depending on Fault Location Probability of Utility Knowledge of
Customers Outage Within Fault Affected 30 Minutes Utility Driver F1
1 Variable* Knowledge of outage F2 1-3 Variable* Knowledge of
outage F3 >100 Good Knowledge that all customers restored F4
>300 Very Good Knowledge that all customers restored F5 >1000
Near 100% Knowledge that all customers restored *depending on
customer being at home.
[0048] System Response to Outages
[0049] In the system 200, the following outage/restoration features
are implemented:
[0050] 1. The collector 116 can provide an outage call to MAS 202
when the collector is affected by an outage.
[0051] 2. The collector 116 can provide a restoration call to MAS
202 when power is restored to the collector.
[0052] 3. The meters 114a/b can send a radio frequency (RF) message
to notify the collector 116 that power has been restored to the
meter site. The collector 116 can make one or more calls to report
the restoration information to MAS 202.
[0053] 4. Once notified of an outage or a restoration condition,
the MAS 202 can provide this notification to an Outage Management
System (OMS) 211 and to MAS operators.
[0054] When equipped with a means to hold up the power supply, an
electricity meter end point 114a/b (REX Meter, A3 Node) in the
system can transmit an outage message when power fails. The
electricity meter 114a/b can be configured to send the message
immediately, or after a configurable delay period. The configurable
(e.g., 1-255 seconds) delay period would typically be set at the
factory, or alternatively could be set via a download from MAS 202
or via customer programming software and an optical communication
probe connected to the meter. The meter will only transmit an
outage message if the outage lasts longer than the outage delay
period. After the delay period, the meter 114a/b will transmit a
number of outage messages (e.g., 3) where each outage message is
transmitted in a randomly selected transmit slot. In the preferred
embodiment, the meter can select from, e.g., 1 of 15 transmit
slots.
[0055] The outage message transmitted by the electricity meter can
be received by any other 2-way node in the system (e.g., 114a or
114b). Each 2-way node has the capability to store multiple
messages (e.g., 8) and forward the message to the collector.
Multiple nodes in the system may receive the same outage message,
thereby increasing the probability that the message is forwarded to
the collector. Nodes that receive an outage exception will attempt
to forward the message to the collector in an exception window. The
node will continue to transmit a message to the collector until the
collector acknowledges receipt of the message.
[0056] The collector 116 can also detect exception conditions as
part of the normal billing read process. When reading billing data
from a node 114a/b, the collector 116 will check if the node has
any exception data that needs to be forwarded to the collector. If
data is available, the collector 116 will read the exception
conditions from the node, clearing the condition from the node and
causing the node to stop transmitting the condition to the
collector 116.
[0057] It should be noted that the device transmitting the outage
message does not need to be an electricity meter. The device could
be a strategically located device, mounted near protective
equipment or at a transformer location. It could also be a device
installed inside a residence to signify that power has been lost to
the site. In the preferred embodiment, the outage notification
feature is included in the electricity meter to minimize cost to
the utility if all accounts are equipped with the feature. A
strategically placed outage notification deployment may be more
cost effectively deployed with non-metering devices, and the
present invention allows for a strategic deployment.
[0058] The collector 116 can be configured to respond in a variety
of ways to the receipt of an outage message. The following options
can be selected via collector configuration parameters per a
particular utility's preferences:
[0059] 1. Make an immediate call to the MAS 202 after receiving an
outage message from an electric meter. While possible, this is not
expected to be the likely operating mode for most utilities.
[0060] 2. Delay for a configurable period of time to allow for the
aggregation of outage information from multiple end points, then
call to notify MAS 202 regardless of whether power has been
restored to some or all of the meters affected by the outage.
[0061] 3. Delay for a configurable period of time (e.g., 1 to 15
minutes) to allow for the aggregation and filtering of outage and
restoration information from multiple end points. After the delay,
the collector 116 may initiate a call to MAS 202 if a meter has
reported an outage but not yet reported a restoration. To improve
the filtering and to limit false alarms, the collector 116 can be
configured to poll each meter 114a/b that reported an outage, using
a lack of a response as an indication that the outage condition
still exists.
[0062] 4. Aggregate the outage and restoration information as
described in options 2 and 3, above, but do not initiate an inbound
call if the number of meters in an outage condition exceeds a
configurable threshold. This scenario assumes that it is a
widespread outage and that customer call-ins will be sufficient to
notify of and determine the extent of the outage. The collector
filter prevents an overload of information to an Outage Management
System (OMS) 211.
[0063] The collector 116 may initiate an inbound communication to
the MAS 202 to report the outage condition. The MAS 202 will
forward the outage information to the outage management system
(OMS) 211, which may also receive outage information through
customer call-ins to a trouble call center. After receiving the
initial report of an outage, either via outage messages from the
AMR system or via a customer call, the OMS 211 can use the system
200 to determine the extent of the outage. To do so, the OMS or a
distribution operator can provide a list of electric meters that it
would like to check for outage conditions. Using a small number of
outage reports, the OMS 211 can probe logical points to determine
if the outage is of type F2, F3, F4, or F5. The list of meters may
be derived from the distribution network topology (i.e., meters on
the same feeder, lateral, or service transformer).
[0064] After receiving the list of meters from the OMS 211, the MAS
202 determines which collector(s) these meters communicate through
and will instruct each identified collector to check for outage
conditions on their subset of meters. The collector(s) involved
will attempt to verify communications to each end point meter in
the list. A lack of communications can be used to indicate a
potential outage and communication to a meter will confirm the
presence of power. The extent to which the system 200 can probe the
outage condition is dependent on which meters in the communication
path are powered. Since the network operates in a hierarchical
repeater chain, an outage at a repeater/meter at a low level
(closer to the collector 116), can affect communications to
multiple downstream meters that may not be in an outage condition.
As with any RF system, lack of communications to a given device
will not always equate to an outage at that device.
[0065] If instructed to poll a large number of meters or all meters
114a/b served by the collector 116, the collector 1116 can use
various algorithms to optimize the time required to check the list
of meters. With a hierarchical system, if a collector 116 is able
to communicate with a level farthest away from the collector, the
collector 116 will know that all meters in the communication path
are powered. Alternatively, the collector 116 could start from the
level closest to the collector 116. If unable to communicate to the
closest level, the collector knows that it cannot communicate to
meters farther down the communication chain.
[0066] After polling the meters identified by the MAS 202, the
collector 116 updates the list with status information to indicate
whether the meter is powered. The status information will indicate
that the meter responded (meter is powered), meter did not respond,
or meter could not be checked due to a failure in the communication
path ahead of the targeted end point. In the case of a
communication path failure, the collector may identify the point in
the communication path that is not responding, possibly identifying
a meter in an outage condition. The MAS 202 may issue the polling
request to the collector and wait for the response as soon as it is
completed, or it may issue the command to the collector and
disconnect the WAN session (i.e., the link between the
communication system 226, subnet/LAN A, subnet/LAN B, etc.) without
waiting for the response. In this scenario, the collector can be
configured to initiate an inbound communication to the MAS 202 to
report that the request has completed. The MAS 202 can retrieve the
information and pass outage or powered status to the OMS 211 for
each of the requested meters. The information available from the
OMS 211 can be passed to utility operators and used to direct crews
to the outage locations.
[0067] In addition to the outage exception message received from a
meter, the collector may be configured to determine if an outage
condition is present based on the communication success rate to a
given meter. In normal operating conditions, the collector
periodically communications with each meter to retrieve register
(e.g. kWh) data and load profile data. Over time, the collector
establishes a communication reliability rate, or performance rate,
for each meter. After a minimum number of attempts to communicate
to a meter have been made, the collector can determine typical
performance rates for a meter flag abnormalities as a potential
outage condition. This functionality is illustrated with the
following example.
[0068] After at least 100 communication attempts to a meter, the
collector will have a communication performance score (e.g. 90/100)
that indicates the likelihood of successful two-way communications
between the collector and the meter. If the collector then fails to
communicate with the meter on successive attempts, the collector
can set a "potential outage" flag to indicate that the meter may be
in an outage condition. The number of failed communication attempts
required to set the "potential outage" flag is configurable based
on the collector to meter communication performance rate. If, for
example, the communication performance rate was 100%, two failed
communication attempts would cause the collector to set the
"potential outage" flag. If, on the other hand, the communication
performance rate was 80%, six successive failed communication
attempts would be required to set the "potential outage" flag.
[0069] The collector may also delay between successive
communication attempts to ensure that a momentary communication
problem does not cause the "potential outage" flag to be falsely
set. The collector's ability to warn of a potential outage
condition provides an outage detection algorithm for cases where
metering points are not equipped with a means to transmit outage
exception messages. The collector's algorithm can also augment
outage detection for systems with outage enabled meters.
[0070] When power is restored to the meter 114a/b, the meter may be
configured to transmit a power restoration message to the collector
116. To avoid multiple restoration messages from a given meter, the
meter can be programmed to delay for a configurable period of time
(e.g., 1 to 10 minutes) prior to transmitting the restoration
message to the collector 116. The delay in the end point meter
prevents a false indication of power restoration, that may occur as
reclosers are operating. The collector 116 can be configured to
delay for a period of time after receiving the first restoration to
allow additional messages to be aggregated prior to initiating a
communication to the MAS 202.
[0071] Once power is believed to be restored to a site, the OMS in
conjunction with MAS 202 can be used to verify that power has been
restored to sites that were reported to be in an outage condition.
The OMS 211 can use either the restoration information as reported
by the end point meter or the OMS 211 can send a list of meters to
the collector 116 and request that the collector confirm power
restoration to the given list. The verification of power
restoration is often times more important to a utility than is the
outage reporting, as it allows the utility to optimize restoration
crews and provide a positive confirmation to customers and to their
systems that power has been restored.
[0072] In addition to the features described above, the MAS 202 may
provide a Geographic Information System (GIS) based network
management component that provides GIS overlay images (shape files)
for: the mesh communication paths, event/alarm information, and
outage/restoration information. This would provide the utility with
geographic shapefile overlays that could be superimposed over their
distribution network topology to gain better insight into what is
actually happening during an outage event down to the level of each
meter/residence. The geographic information that can be provided
for visual overlay will include reported outages, reported
restorations, polled information to show confirmed power on and
probable power out locations. For utilities with an Outage
Management System (OMS) 211, the geographic network image could
augment the information provided by the OMS 211. For utilities
without an OMS, a network image maintained by the system 200 may be
used to assist the distribution operators with geographic
information to augment other methods and tools used to diagnose
outage and restoration efforts.
[0073] Exemplary Scenarios
[0074] The following examples of outages in the various scenarios
help illustrate the outage and restoration process.
[0075] Fault at F1:
[0076] For a fault at F1, the meter may sense a decrease in voltage
due to the fault, but the meter would remain powered after the
fault is cleared by the house circuit breaker. If the customer
calls the utility to report an outage, the utility may do an
on-request read of the meter voltage. Since the REX meter is
connected on the source side, it will indicate that voltage is
present; allowing the utility to be aware the problem is on the
customer site.
[0077] Fault at F2:
[0078] For a fault at F2, the REX meter would lose power, increment
an outage counter, and stop responding to network RF messages.
Normal, periodic reads from the collector are not sufficient to
quickly signal an outage condition and report the outage to MAS.
The probability of the utility becoming quickly aware of the fault
due to customer call-ins is not good, unless the meter affected by
the outage is equipped with outage notification hardware. If the
utility is notified, the outage management system could then
determine the extent of the outage by providing a list of suspect
meters to MAS. The list of meters would be those around the meters
identified by customer call-ins necessary to determine the extent
of the outage. Then, MAS would distribute the meter list to the
collector or collectors that serve the meters in the list. Each
collector would receive a list consisting of only the meters that
are a part of its local area network. The customer call-in
information would be augmented by the outage information provided
by the system, allowing crews to be dispatched in a logical and
efficient manner.
[0079] Once the fault is cleared and power is restored, the meter
transmits a restoration message to the collector and the collector
will forward the restoration information to MAS. MAS can then
provide this restoration information to an OMS for confirmation of
power restoration. The restoration information can be used to
confirm outage locations that have been cleared and allow work
crews to be focused on areas that have not yet been confirmed
restored. In addition to the restoration message from the meter,
the OMS can be used to "ping" a meter to verify power restoration
after a crew has completed a field repair. The ping to the target
meter is made by the source of the ping (e.g., the OMS) to verify
that the target meter is powered and responsive.
[0080] Fault at F3:
[0081] For a fault at F3 (distribution lateral), all meters past
the fault point would register an outage and increment their outage
counter. Using the assumptions of Table 2, more than 100 electric
meters would experience the same event. The probability of the
utility becoming quickly aware of the fault due to customer
call-ins is good. As described for faults at F2, the OMS in
conjunction with MAS could determine the extent of the outage and
verify power restoration.
[0082] Fault at F4:
[0083] For a feeder fault at F4 past a recloser, the meters would
sense multiple outages due to the voltage fluctuations caused by
recloser operations. Note that the time between recloser operations
is typically in the milliseconds to seconds range, but some units
may be programmed for up to 200 seconds for 4 recloser operations.
Thus the recloser cycle may not be complete until 3 recloser trip
times and 600 seconds closing delay time. Also, the fault location
and resistance will affect the voltage seen by the meters. Using
the assumptions of Table 2, more than 1000 electric meters would
experience the same event. The probability of the utility becoming
quickly aware of the fault due to customer call-ins is very high,
and the system can then be used to determine the extent of the
outage as well as to monitor the progress in restoring power to
affected customers.
[0084] Fault at F5:
[0085] For a fault at F5, the meters act the same as in the
previous Fault at F4 analysis; however, over 3000 electric meters
are affected and the utility would probably become aware of the
outage very quickly via the OMS.
[0086] While systems and methods have been described and
illustrated with reference to specific embodiments, those skilled
in the art will recognize that modification and variations may be
made without departing from the principles described above and set
forth in the following claims. Accordingly, reference should be
made to the following claims as describing the scope of disclosed
embodiments.
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